1. Field of the Invention
The present invention generally relates to a heat dissipation device, and more particularly to a heat sink for an electronic device.
2. Description of Related Art
An electronic device such as a central processing unit (CPU) generates heat during operation and temperature thereof will increase beyond its normally acceptable range unless the heat is removed effectively. The temperature increase results in instability and failure of operation of the electronic device. For ensuring the normal operation of the electronic device, heat dissipation is indispensable.
Generally, a heat sink is applied to the electronic device for dissipating heat generated thereby. With the continuing boom of integrated circuits technology, designs on heat sinks change quickly. However, vibration and noises are still the problems, which must be faced and resolved.
A typical heat sink is disclosed in U.S. Pat. Publication No. 2004/0052051. In this patent publication, a heat sink comprises a base for absorbing heat and a plurality of fins stacked together parallel to each other for dissipating heat. A heat pipe is attached to the base and extends through the fins. The heat sink draws the heat from a heat source by the base, then transfers it to the fins via the heat pipe, and dissipates it from the fins outwards to a surrounding environment. In order to maximize heat dissipation capability, the fins are made to have a larger size for larger heat dissipation area, and a small thickness so that a high fin density can be provided on the base thereby further increasing the heat dissipation area. On the other hand, to get a better heat-spreading in the fins, the heat pipe passes through a middle portion of the fins. Outer portions of the large fins which are far away from the middle portion, especially outer edges of the fins, are subjected to deflection when the heat sink is mounted with a fan providing a forced airflow through the fins, or when a system airflow passes through the fins. Shock or vibration, and noises are thereby generated. The vibration will be partly transferred to the base of the heat sink and even to the electronic device, adversely impacting a normal operation of the electronic device, such as stability or useful life thereof. The impact is even more considerable when a resonant vibration occurs. Adding heat pipes to the heat sink to strengthen connection between the base and the fins may be considered; however, this increases cost of the heat sink significantly.
Therefore, an improved heat sink assembly which overcomes above problems is desired.